Objectives: (1) To develop more precise methods of electromyography (EMG) recording and analysis; (2) to establish better EMG indices of early myopathic or neuropathic involvement; (3) to improve the value of the EMG in distinguishing the neural vs. myopathic basis of atypical disorders; (4) to investigate mechanisms regulating motor unit recruitment in normal subjects and those with neuromuscular disorders; (5) to correlate the electrical behavior of motor units with their histochemically defined properties; (6) to use clinical electrophysiologic parameters to evaluate course of disease and response to treatment; (7) to use electrophysiologic techniques to analyse induced animal-models of human neuromuscular diseases; (8) to study certain very limited aspects of normal muscle fiber function from the basic point of view.